Threadform having crest to root thread compound relief areas

ABSTRACT

A connection includes a first tubular member having a first screw threadform defined by a first plurality of crests, roots, and flanks, where each flank separates each crest from each root. The connection also includes a second tubular member having a second screw threadform defined by a second plurality of crests, roots, and flanks, where each flank separates each crest from each root. The crests and roots are substantially axial to the tubular members and the flanks are substantially radial to the tubular members. The first tubular member and the second tubular member are configured to connect when the first threadform engages with the second threadform. Thread compound relief spaces are formed between the first plurality of crests and the second plurality of roots when the first and second tubular members connect.

TECHNICAL FIELD

The present application relates to tubular connections, and moreparticularly, to a tubular connection threadform having crest to rootthread compound cavities.

BACKGROUND

This section is intended to introduce various aspects of art that may berelated to various aspects of the present techniques, which aredescribed and/or claimed below. This discussion is believed to behelpful in providing background information to facilitate a betterunderstanding of the various aspects of the present disclosure.Accordingly, it should be understood that these statements are to beread in this light, and not as admissions of prior art. The followingdescriptions and examples are not admitted to be prior art by virtue oftheir inclusion in this section.

The oil and gas industry is drilling upstream production wells ofincreasing depth and complexity to find and produce raw hydrocarbons.The industry routinely uses steel pipe, considered an Oil CountryTubular Good (OCTG) to protect the borehole (i.e., casing) and tocontrol the fluids produced within the pipe (i.e., tubing). Such pipes,including casing and tubing, are made and transported in relativelyshort segments and installed in the borehole one segment at a time, witheach segment being connected to the next. As the search for oil and gashas driven companies to drill deeper wells, pipes may be subject toincreased complexity and magnitude of forces throughout their lifespansdownhole. Industry demands have grown for casing, tubing, and connectorshaving increased tensile and pressure strengths. Furthermore, thedeveloping area of deviated and horizontal wells have exacerbated thistrend, further adding increased torsional loads as another requirementfor casing and tubing connectors.

Connectors have been designed with varying thread, shoulder, and sealconfigurations. For example, two general connector thread configurationsinclude a threaded and coupled connector and an integral connector. Athreaded and coupled connector includes a pin (i.e., a male threadedend) machined on relatively long joints of pipe and joined by a box(i.e., a female threaded end) machined on a relatively short coupling.An integral connector includes a pin threaded on a full-length pipeconnected to a box threaded on another full-length pipe, and pin and boxends may be threaded onto opposite sides of each full-length pipesegment so that each segment may be connected for a length of aborehole. The various connection configurations may involve applying athread compound to the pin and box threads as they are joined together.This thread compound, sometimes referred to as pipe dope or thread dope,may provide lubrication as pipes or connections are assembled and mayfill voids between threads.

As industry demands connectors with increasingly high tensile strength,pressure strength, and torque, etc., the general features of connectorsmay be designed and engineered to meet downhole performance criteria.Connectors may be further designed to incorporate intentional voids forcontaining thread compound while meeting high performance criteria.

Prior efforts have to been made to design connectors with voids tocontain thread compound. For example, U.S. Pat. No. 7,717,478 disclosesa design with a plurality of “interruptions” spaced periodically alongthe thread form, but (at column 10, line 63—column 11, line 10)expressly teaches away from a connector that includes a void forcontaining thread compound that extends from one end of the thread helixto the other.

Similarly, U.S. Pat. No. 7,810,849 discloses “perturbations” that create“localized” areas of reduced clearance that may serve as a void forcontaining thread compound. However, this patent also discloses (atcolumn 11, lines 59-62) that “it may be undesirable to constructs [sic]a threaded connection with interference or reduced clearance throughoutthe entire connection because such a construction may lead to prematurefailure of the connection.”

Accordingly, there is a need for a connector with an intentional voidfor containing thread compound, wherein the void extends along theentire axial length of the threadform, so as to maximize the volume ofthread compound that can be accommodated. This configuration helps toavoid hydraulic locking, which may occur when the void has insufficientvolume to accommodate all of the thread compound that was applied.Hydraulic locking may cause problems because it can lead to inaccuratetorque readings, which may interfere with both assembly and disassemblyof the connector.

Alternatively, an increased volume of thread compound may beaccommodated by a plurality of voids between each corresponding pair ofthread roots and thread crests—but not both—along the entire axiallength of the threadform.

Extending the void along the entire axial length of the threadform canprovide other benefits, as well. For example, it is generally easier tomachine this configuration, as compared to a threadform that onlyincludes a void along a portion of its axial length. In addition, ifthread compound is applied unevenly along the axial length of thethreadform, extending the void along the entire axial length providesmore flexibility to accommodate uneven application than a configurationthat only includes a void along a portion of its axial length.

SUMMARY

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

In one embodiment, a connection includes a first tubular member having afirst screw threadform defined by a first plurality of crests, a firstplurality of roots, and a first plurality of flanks, where each flankseparates each crest from each root. The first plurality of crests androots are substantially axial to the first tubular member while thefirst plurality of flanks are substantially radial to the first tubularmember. The connection also includes a second tubular member having asecond screw threadform defined by a second plurality of crests, asecond plurality of roots, and a second plurality of flanks, where eachflank separates each crest from each root. The second plurality ofcrests and roots are substantially axial to the second tubular memberand the second plurality of flanks are substantially radial to thesecond tubular member. The first tubular member and the second tubularmember are configured to connect when the first threadform engages withthe second threadform. Thread compound relief spaces are formed betweeneach of the first plurality of crests and each of the second pluralityof roots, throughout the axial length of the first and second screwthreadforms. In some embodiments, a contact region forms between aportion of the first plurality of flanks and a portion of the secondplurality of flanks when the first and second tubular members connect.In some embodiments, the thread compound relief spaces are formed bymaking the axial height of the first plurality of flanks less than theaxial height of the second plurality of flanks

In some embodiments, the first tubular member has a pin end and thesecond tubular member has a box end, and the thread compound reliefspaces are formed between crests of the pin end and roots of the boxend. The thread compound relief spaces may have an axial height that is5% to 40% of an axial height of the first plurality of flanks, 5% to 40%of an axial height of the second plurality of flanks, or both. In someembodiments where the thread compound relief spaces are formed betweencrests of the pin end and roots of the box end, the first plurality offlanks have an axial height that is 60% to 95% of an axial height of thesecond plurality of flanks, the second plurality of flanks have an axialheight that is 60% to 95% of an axial height of the first plurality offlanks, or both.

In some embodiments, additional thread compound relief spaces are formedbetween each of the first plurality of roots and each of the secondplurality of crests, throughout the axial length of the first and secondthreadforms, such that the thread compound relief spaces combine to forma substantially continuous void between the corresponding roots andcrests throughout the axial length of the first and second screwthreadforms. In these embodiments, the thread compound relief spacescomprise an axial height that is 5% to 40% of an axial height of thefirst plurality of flanks, 5% to 40% of an axial height of the secondplurality of flanks, or both. In some embodiments where the threadcompound relief spaces are formed between crests of the pin end androots of the box end and the roots of the pin end and the crests of thebox end, the first plurality of flanks have an axial height that is 60%to 95% of an axial height of the second plurality of flanks, the secondplurality of flanks have an axial height that is 60% to 95% of an axialheight of the first plurality of flanks.

The invention may also comprise a method for forming a tubularconnection like that described above, wherein the method comprisesapplying thread compound to the first screw threadform of the firsttubular member and rotating one of the first tubular member and thesecond tubular member relative to each other, such that the first screwthreadform engages with the second screw threadform. Thread compound mayalso be applied to the second screw threadform as part of this method.

In another embodiment, a method includes moving a first tubular memberrelative to a second tubular member, such that a pin end of the firsttubular member enters and axially overlaps with a box end of the secondtubular member. The method further includes rotating the first tubularmember relative to the second tubular member, such that a firstthreading on the first tubular member engages with a second threading onthe second tubular member. The method then includes connecting the firsttubular member to the second tubular member, such that a length of boxthreading of the box end substantially covers a length of pin threadingof the pin end. The pin threading includes pin crests and pin roots thatare substantially axial to the first tubular member, where the pincrests and pin roots are each separated by pin flanks that aresubstantially radial to the first tubular member. The box threadingincludes box crests and box roots that are substantially axial to thesecond tubular member, where the box crests and box roots are eachseparated by box flanks that are substantially radial to the secondtubular member. A thread compound relief space forms between the pincrests and the box roots once the first and second tubular members areconnected.

In some embodiments, the method further comprises disposing threadcompound on one or both of the pin end of the first tubular member andthe box end of the second tubular member. The thread compound reliefspace is suitable for containing the thread compound. Furthermore, insome embodiments, connecting the first tubular member to the secondtubular member includes contacting a portion of pin flanks to a portionof box flanks. The contacting portion may include interfering contactbetween a portion of the pin threading and a portion of the boxthreading. Additionally, in some embodiments, connecting the firsttubular member to the second tubular member comprises contacting pincrests with box roots and contacting box crests with pin roots alongonly a portion of a length of the pin end and a corresponding length ofthe box end.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present techniques are described with reference tothe following figures. The same numbers are used throughout the figuresto reference like features and components. Various embodiments mayutilize elements and/or components other than those illustrated in thedrawings, and some elements and/or components may not be present invarious embodiments. Elements and/or components in the figures are notnecessarily drawn to scale.

FIG. 1 is a schematic view a threadform having two ridge segments andtwo groove segments;

FIGS. 2-5 are schematic views of threads during the makeup sequence ofmembers;

FIG. 6 is a schematic view of a stab flank in a fully made upconnection;

FIGS. 7-10 are schematic views of threads during the makeup sequence ofmembers, in accordance with embodiments of the present techniques;

FIG. 11 is a schematic view of one embodiment of a threadform havingthread compound relief between the crest and root of two connectedmembers of a connection; and

FIG. 12 is a schematic view of one embodiment of the invention having awedge threadform.

DETAILED DESCRIPTION

Tubular connectors generally include tubular segments that are connectedwhen a tubular segment having a male threaded pin end is connected withanother tubular segment having a female threaded box end. The pin andbox are designed to be joined together such that the tubular segmentsare sealed to prevent the passage of liquid or gas across the threads ofthe assembled connection. The process of joining the pin and boxtogether, sometimes referred to as make-up, may involve applying athread compound to the pin and box threads in preparation of assemblingone tubular member having a pin end with another tubular member having amating box end. The thread compound, sometimes referred to as pipe dopeor thread dope, may provide lubrication during make-up and may also fillvoids between the pin and box threads.

The schematic diagram of FIG. 1 shows a partial profile 30 of athreadform having two ridge segments 32 a, 32 b and two groove segments34 a, 34 b. The threadform utilizes a square or near-square form havinga stab-flank 36 and load-flank 38 extending between crest 40 and root42. The pitch-line 44 is shown in dashed line form. Thread compound 70may be applied to the threadform of a tubular member in preparation ofassembling one tubular member with another. It may be recommended toapply a certain amount of thread compound 70; for example, a connectionmanufacturer may recommend applying thread compound 70 such that itreaches one-third of the height of the ridges 32. However, in practice,operators may not always carefully control how much thread compound 70is applied, and may often apply more than the recommended amount. Theamount of thread compound 70 depicted in the drawings of presentdisclosure is representative only of an amount of thread compound 70which may be applied during operation.

Referring now to FIGS. 2-5, a tubular connection make-up sequence isdepicted for a representative pin member 80 and box member 82, bothshown only in partial cross-section. The make-up sequence may involverotating one member, for example, the pin member 80, towards and withrespect to the other member, for example, the box member 82. The make-upsequence may further involve the application of thread compound 70,which may be compressed and/or displaced between the pin member 80 andbox member 82 during make-up. While the thread compound 70 is depictedas disposed over the pin member 80, it should be noted that threadcompound 70 is sometimes applied to either the pin member 80, the boxmember 82, or both, in various quantities.

During the first turn, as depicted in FIG. 2, stab flank engagement isbetween the clearance surfaces 54, 54′ of the two threaded members, andthread compound 70 may be disposed between the crest 40 of the pin 80and root 42′ of the box 82 and/or between the root 42 of the pin 80 andcrest 40′ of the box 82. The load flanks may be drawn closer together asthe thread is rotated into closer engagement. If the thread of themembers has a cam surface 52, 52′, as shown, as the threaded assemblyenters its second turn as shown in FIG. 3, stab flank contact shiftsfrom the clearance surfaces 54, 54′ to the cam surfaces 52, 52′. If not,assembly during the second turn remains on the clearance flank. At thispoint, the thread compound 70 may be touching or almost filling theclearance between the crest 40 of the pin 80 and root 42′ of the box 82and/or between the root 42 of the pin 80 and crest 40′ of the box 82.Rotation of one member into the other member decreases the clearancebetween load flanks. In the example illustrated in FIG. 4, at the end ofthe second turn, the clearance is almost closed. Thread compound 70 maybe compressed in the clearance between the crest 40 of the pin 80 androot 42′ of the box 82 and/or between the root 42 of the pin 80 andcrest 40′ of the box 82.

As the connection enters its third turn, the thread groove and threadridge's load flanks engage, or are moved closer together, as depicted inFIG. 5. As the connection continues to be engaged, the base surface ofthe stab flank and the load flank continue to slide upon the respectivemating surfaces until the root and crests of the thread engage. Threadcompound 70 may be compressed in the small clearances and voids betweenthe pin 80 and box 82.

FIG. 6 is an enlarged view of the stab flanks of the thread of FIG. 5 atfull thread assembly. As shown in FIG. 6, thread compound 70 may stillbe disposed between ridges 32 of the pin 80 and the ridges 32′ of thebox 82. In some connections, the stab and load flanks may be intended tocontact or interfere. The thread compound 70 applied during make-up maygather between voids of the two members, such as voids 72 which areformed between the angled surfaces of the stab and load flanks. However,due to various parameters such as the shape of the threadforms and thequantity, location, and properties of the thread compound 70, threadcompound 70 may remain between thread flank surfaces that are intendedto contact or interfere, such as between the intended contact area 74.The contact or interference of thread flank surfaces may be intended toincrease pressure strength of the made-up connection. However, thecontainment and/or compression of thread compound 70 between surfaces oftwo engaging tubular members around an intended contact area 74(sometimes referred to as dope entrapment), may potentially alter ordecrease the pressure strength and performance of an engaged connectionunder certain circumstances.

In one or more embodiments of the present techniques, the threadforms ofthe pin member 80, the box member 82, or both, may be designed such thatwhen the two tubular members are fully made up, a clearance remainsbetween the crests and roots of the pin member 80 threads and box member82 threads. This clearance, which may also be described as a void,pocket, recess, space, area, etc., may provide relief from threadcompound entrapment, as the thread compound may gather within thisintentional clearance space, rather than remaining disposed betweenthread surfaces that are intended to contact or interfere. The presentembodiments of threadforms having thread compound relief spaces may haveareas designed to contain more thread compound than a typicalthreadform. Thread compound may be displaced to these relief spaces,thereby decreasing the amount of thread compound remaining betweenthread surfaces intended to contact, and increasing pressure strengthand other performance parameters.

FIGS. 7-10 depict a tubular connection make-up sequence representing oneor more embodiments of the present techniques, where the pin member 80and/or the box member 82 are designed with thread compound relief spaces90 between the crests 40 and roots 42 of the two members 80 and 82. Therelief spaces 90 include an increase in clearance between the crests 40and roots 42 compared to a typical threadform, and may refer tothreadform designs where a clearance between crests 40 and roots 42 isintended to remain after the pin and nose member is fully made-up. Insome embodiments, the crests 40 and roots 42 may not be in contact evenwhen tubular members are made-up. In accordance with the presenttechniques, tubular members are made-up, engaged, or connected, when allridges 32 of a pin 80 or box 82 are positioned within groove segments 34of a mating box 82 or pin 80. In other words, the tubular members aremade up when the length of the threading on the pin 80 substantiallyoverlap with the length of the threading on the box 82.

The make-up sequence may involve rotating one member, for example, thepin member 80, towards and with respect to the other member, forexample, the box member 82. The number of turns or rotation of onethreaded member into the other threaded member producing the assemblysequence may vary with the geometric proportions of the individualthreadform used for the members. The make-up sequence may furtherinvolve the application of thread compound 70, which may be displacedbetween the pin member 80 and box member 82 during make-up. While thethread compound 70 is depicted as disposed over the pin member 80, itshould be noted that thread compound 70 may be applied to the pin member80, the box member 82, or both, in various quantities.

During the first turn, as depicted in FIG. 7, the stab flank engagementis between the clearance surfaces 54, 54′ of the two threaded members,and thread compound 70 may be disposed between the crest 40 of the pin80 and root 42′ of the box 82 and/or between the root 42 of the pin 80and crest 40′ of the box 82. The load flanks may be drawn closertogether as the thread is rotated into closer engagement. If the threadof the members has a cam surface 52, 52′, as shown, as the threadedassembly enters its second turn as shown in FIG. 8, stab flank contactshifts from the clearance surfaces 54, 54′ to the cam surfaces 52, 52′.If not, assembly during the second turn remains on the clearance flank.

As shown in FIG. 8, the load flanks may be drawn closer together as thethread is rotated into closer engagement. Due to the relief spaces 90,the thread compound 70 may have more space between the crest 40 of thepin 80 and root 42′ of the box 82 and/or between the root 42 of the pin80 and crest 40′ of the box 82 than it would have in a connection havinga typical threadform. As illustrated in FIG. 9, at the end of the secondturn, the clearance is further decreased. Thread compound 70 may almostfill the clearance between the crest 40 of the pin 80 and root 42′ ofthe box 82 and/or between the root 42 of the pin 80 and crest 40′ of thebox 82. As the connection enters its third turn, the thread groove andthread ridge's load flanks engage, or are moved into substantivecontact, as depicted in FIG. 10. Thread compound 70 may be displacedfrom the stab and load flanks of the threadforms and may instead becontained in the thread compound relief areas 90 between the pin 80 andbox 82. As shown in FIG. 10, thread compound relief areas 90 may extendthroughout the axial length of pin 80 and box 82. In other words, athread compound relief area 90 may exist between each crest 40 of pin 80and root 42′ of box 82, and also between each crest 40′ of box 82 androot 42 of pin 80. This pattern forms, in effect, a continuous threadcompound relief area extending from one end of the connection to theother. In this way, the design of an embodiment of the present inventionprovides substantially greater volume for thread compound relief thanprior designs.

FIG. 11 depicts one or more embodiments of a threadform having threadcompound relief areas between the crest 40 of the pin 80 and the root42′ of the box 82. As shown in FIG. 11, thread compound 70 may besubstantially contained in the thread compound relief areas between thecrest 40 of the pin 80 and root 42′ of the box 82. In some connections,the stab and load flanks may be intended to contact or interfere. Thethread compound 70 applied during make-up may displace from the flanksof the pin 80 and box 82 and may gather between voids of the twomembers, such as the voids 72 formed between the angled surfaces of thestab and load flanks. Additionally, thread compound 70 may be containedin the thread compound relief areas 90 between the crest 40 of the pin80 and root 42′ of the box 82. In accordance with the presenttechniques, the amount of space available to contain thread compound 70may be sufficient to contain thread compound 70 such that intendedcontact areas 74 of surfaces of two engaging tubular members may contactor interfere as intended.

It should be appreciated that the thread compound relief areas 90 of thepresent techniques may involve any combination of lowering the height ofthe crest 40 of the pin 80, extending the depth of a root 42 of the pin80, lowering the height of the crest 40′ of the box 82, and extendingthe depth of the root 42′ of the box 82. As used herein, lowering theheight of the crest refers to a decreased height of the crest such thata clearance or space remains between the crest and the root it mateswith once the tubular member is fully engaged. Likewise, extending thedepth of the root refers to an increased depth of the root such that aclearance or space remains between the root and the crest it mates withonce the tubular member is fully engaged.

For example, one or more embodiments depicted in FIG. 10 may includelowering the height of the crest 40 of the pin and/or extending thedepth of the root 42′ of the box 82, as well as extending the depth ofthe root 42 of the pin and/or lowering the height of the crest 40′ ofthe box 82. As shown in FIG. 10, the made-up pin and box members 80 and82 have thread compound relief areas 90 between both the crest 40 of thepin 80 and the root 42′ of the box 82 and the root 42 of the pin 80 andthe crest 40′ of the box 82. However, one or more embodiments depictedin FIG. 11 may include only lowering the height of the crest 40 of thepin and/or extending the depth of the root 42′ of the box 82, as themade-up pin and box members 80 and 82 have thread compound relief areas90 only between the crest 40 of the pin 80 and the root 42′ of the box82. Likewise, other embodiments of the present techniques may includeonly extending the depth of the root 42 of the pin and/or lowering theheight of the crest 40′ of the box 82 such that made-up pin and boxmembers 80 and 82 have thread compound relief areas 90 between the root42 of the pin 80 and the crest 40′ of the box 82.

While square or near-square threadforms are depicted in the presentdisclosure, it should be noted that the present techniques of includinga space between the crest and root of a connected pin and box to containthread compound may be applicable to other thread shapes, includingbuttress threads, wedge threads, or any other threads having anapproximate crest portion and root portion in the threadform. Forexample, FIG. 12 represents one or more embodiments having a wedgethreadform. Certain features of different embodiments may be combineddepending on the shape of the threadform. For example, the thread ridges92 and 92′ of the pin 80 and box 82, respectively, may each have angledstab and load flanks. A connection having a wedge threadform may havethread compound relief areas 90 between both the crest 40 of the pin 80and the root 42′ of the box 82 and the root 42 of the pin 80 and thecrest 40′ of the box 82 while maintaining sufficiently high pressurestrength, due to the angled flank configuration of the wedge threadform.

The threaded tubular connection of the present application may furtherbe used in an integral joint or in a coupled joint for tubular members.In an integral joint the pin and box members are joined integrally tothe ends of the tubular members. In a coupled joint, a threaded couplingjoins the threaded ends of the tubular members. The threaded tubularconnection of the present invention is also applicable to all types ofoil field tubulars including drill pipe, casing, and tubing. Theconnection may be used on plain end pipe, cold formed swaged ends, orhot forged upset ends.

Furthermore, in various embodiments, the thread compound relief area 90size may vary depending on the shape of the tubular member threadforms.In some embodiments, a height of the thread compound relief area 90 maybe approximately 5% to 40% of the height of the groove segment thatcontains it, or in some embodiments, 5% to 20% of the height of thegroove segment that contains it. Additionally, in some embodiments, thethread compound relief area 90 size may be a function of a ratio of aheight of side flanks of a pin member 80 with respect to a height ofside flanks of a box member 82. For example, in some embodiments, theside flanks of a pin member 80 may have a height that is 60% to 95% theheight of the side flanks of a box member 82, or the side flanks of abox member 82 may have a height that is 60% to 95% of the height of theside flanks of a pin member 80, or both. Additionally, the size of thethread compound relief areas 90 may vary throughout the length ofthreading on a pin member 80 and a box member 82.

In some embodiments, the tubular connection is typically included in thebroad group identified as slim-line, high performance connections. Theconnection may be used in various embodiments such as integralflush-joint, with or without crimped sections, integral swaged with orwithout swaged sections, hot-forged upset on one or both members, orcoupled with or without crimped pin ends. For either an integral orcoupled connection, it is envisioned that the threadforms can be used inconjunction with other common premium connection features such as,without limitation, one or more metal seals (both internal andexternal), one or more torque shoulders for positive position stop(inside, outside, or center), and run-in/run-out threads.

Many modifications and other implementations set forth herein will beapparent having the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the systems and methods described herein are not to belimited to the specific implementations disclosed and that modificationsand other implementations are intended to be included within the scopeof the appended claims. Although specific terms are employed herein,they are used in a generic and descriptive sense and not for purposes oflimitation.

The invention claimed is:
 1. A connection comprising: a first tubularmember comprising a first screw threadform defined by a first pluralityof crests, a first plurality of roots, and a first plurality of flanks,wherein each flank separates each crest from each root, and wherein thefirst plurality of crests and roots are substantially axial to the firsttubular member and the first plurality of flanks are substantiallyradial to the first tubular member; and a second tubular membercomprising a second screw threadform defined by a second plurality ofcrests, a second plurality of roots, and a second plurality of flanks,wherein each flank separates each crest from each root, and wherein thesecond plurality of crests and roots are substantially axial to thesecond tubular member and the second plurality of flanks aresubstantially radial to the second tubular member; wherein the firsttubular member and the second tubular member are configured to connectwhen the first threadform engages with the second threadform; andwherein a first plurality of thread compound relief spaces is formedbetween each of the first plurality of crests and each of the secondplurality of roots, throughout the axial length of the first and secondscrew threadforms; wherein the first tubular member comprises a pin endand the second tubular member comprises a box end, and the threadcompound relief spaces are formed between crests of the pin end androots of the box end; and wherein the thread compound relief spacescomprise an axial height that is 5% to 10% of an axial height of thefirst plurality of flanks.
 2. The connection of claim 1, wherein thefirst plurality of roots and the second plurality of crests come intodirect contact when the first and second tubular members are connected.3. The connection of claim 1, wherein the thread compound relief spacescomprise an axial height that is 5% to 10% of an axial height of thesecond plurality of flanks.
 4. The connection of claim 1, wherein asecond plurality of thread compound relief spaces is formed between eachof the second plurality of crests and each of the first plurality ofroots throughout the axial length of the first and second threadforms,such that the first plurality of thread compound relief spaces andsecond compound relief spaces combine to form a substantially continuousvoid between the corresponding roots and crests throughout the axiallength of the first and second screw threadforms.
 5. The connection ofclaim 1, wherein a contact region forms between a portion of the firstplurality of flanks and a portion of the second plurality of flanks whenthe first and second tubular members connect.
 6. The connection of claim1, wherein the first plurality of thread compound relief spaces isformed by making the axial height of the first plurality of flanks lessthan the axial height of the second plurality of flanks.